GTOguy

Lets not get off track here. If the noise went away with the plug wire off as I suggested it might, you need to pull the oil pan and check the #4 rod bearing. Most likely it'll have excessive clearance on the big end. Very easy to check. And 99% likely to be your problem.

jimh_1962

If it was me I would not touch it until I talked to the builder. The builder should take responsibility for his/her work.

Nowhere Man

If the studs are pulling out of the heads it would cause that right

MikeM

Exhaust leak at the manifold was my first thought. Also, the easiest one to check and take off the list or fix.

GTOguy

When running down an exhaust leak, if you retard the ignition timing, it will become more evident and easier to find.

MikeM

Have you ever heard the term when speaking of Model A Ford, to "shove the spark up and listen to her (exhaust) cackle"?

karkrafter

GTO guy never fails to teach me something....


Please explain? What does it do to change the sound?


[But a stethoscope is way easier, you can make one from a piece of brake line ]

MikeM

It makes the engine labor and the exhaust to hit harder.

GTOguy

Mike, I also have and drive a stock 1915 Ford Model T.....you can knock the spark to full retard and literally count the explosions...about 200 RPM engine speed!

Ktholin

I did speak with the rebuilder today and another mechanic I know. My plan is to recheck the valve lash on #4, drain the oil and check for particles. I then may drop the oil pan to inspect the rod bearing. This is a bit beyond my experience level, but I would like to see if I can narrow possibilities down (or eliminate them) before I pull the motor.

Ktholin

Yeah, thats kinda of my plan right now.

Ktholin

It doesn't sound to me like an exhaust leak. Its more of a distinctive tapping sound. I did remove the right side headers checked the gasket and reinstalled. Tapping still present.

Ktholin

I did speak to the rebuilder today and he was helpful. We are trying to narrow down the possibilities before I have to pull the motor. He is about 50 miles away, which precludes me driving there.

jimh_1962

It sounds like its time to pull engine and get it back to the rebuilder's shop. Let the engine shop decide what happened to the engine. This is why you paid someone to build your engine. If I did the work (rebuilt my own engine) then I would go down the inspection route by pulling the pan and intake.

How many miles on the engine after the rebuild?
Did you break in the cam properly?
Did you do a leak down, compression or vacuum test?
How was the oil pressure when you started the engine the first time?

This might tell you more if you want to check things out. At this point, I would pull the intake and check the lifters and maybe not the oil pan. Definitely, drain the oil and inspect the filter and bottom of the oil pan. That's not that muck work and really is not going to prevent your rebuilder's work. You might not want to drop the pan unless your engine builder is okay with you doing that. At some point, you do not want to void any "warranty".

If the lifters are fine then pull the engine with the intake off, stop there and and take it to the person's shop. I would first tell the engine builder that the intake is coming off to check the lifters.

karkrafter

Fellas, It's NOT the lifters, they are solids.


Don't bring it 50 miles, gotta be a old time wrench in your town who can listen to it.


Is it worse cold? If so piston


Is it worse hot? Then its a rod

GTOguy

Noisy lifters will still be noisy with the plug wire pulled, because they are still moving the pushrods and rockers and valves. The only thing that goes quiet when you disable the ignition is a bad rod bearing, or possibly bad piston or wristpin. But 99% of the time, its the big end rod bearing. Do what you feel is best. (I'm an auto mechanic with almost 40 years of experience, not your average peanut gallery yahoo, although I sure try to be!) Lots of guys here have forgotten more about these cars than I'll ever know. However, I DO know about rod knocks, and how to find them.

Frankie the Fink

The OP can rent a U-haul trailer for about $48/day if he's an AAA or AARP member; I've driven more than one car hundreds of miles (and for years in one case) with rod knock and it'll drive up on a trailer just fine.

I'd have the whole thing at the mechanic's shop to get it diagnosed before I pulled the motor... There's clearly something wrong with the build and I'd want to diddle with things the least amount possible if I was going after a warranty repair.

But, that's just me and I can be a p_ick when it comes to getting ripped off...

Randy G.

A rod bearing or wrist pin is pretty easy to hear. Let it idle, put your thumb on the throttle linkage and move the rpm up above idle and release it. At the hit of the throttle the noise gets louder for a tick or two or three then sometimes levels back out. Depending on how far gone it is, as the engine decelerates back to idle the knock goes quiet for a few revolutions of the crank because the excessive rod journal or pin clearance is being back loaded.

jimh_1962

I guess that's my point the shopp should do it. He should not need to take anything apart on the bottom end if the shop warranties their work.

Randy G.

Pulling anything apart would give them justification for voiding any warranty as well.